Dogs are individuals. Although some traits are more coming this or that breed, most dogs are much alike. Breeding and early socialization are very important. I often say follow your heart when choosing a breed. Then switch to your brain when it comes to picking one within a breed. I would say the same thing if you wanted a Pit Bull, Rottweiler, Doberman, Poodle, or Golden. They all come in nasty and nice.
I hope you can talk your mother out of Craig's list. It will not be the best place to find a well bred, healthy, sound temperament dog. If you want a puppy, you are going to have to sort through and find a good breeder and pay a real price.
Finding a good breeder and purchasing a puppy that will make a good pet is very difficult. Almost nobody is intentionally breeding dogs to be nice pets. Most of your so called reputable breeders are breeding for show or something. They may say the puppies they don't keep for their purpose make great pets, but the truth is that the parents were selected for other than health and temperament. Often they keep the puppies in the kennel too long and they miss the important early socialization puppies need to live in the house with people.
Next are the disreputable breeders. They breed any 2 registered dogs they can lay a hold of looking only at the money they can make selling them to pet stores. Pet store puppies are easy to find, but difficult to socialize into nice pets, perhaps difficult to even keep alive. You will not get what you pay for at a pet store. You would do as well taking your chances at the animal shelter.
One of the best sources for dogs with a predictable personality is the rescue
Dogs. These are dogs that lost their home, but were taken into a foster home
To be retrained as necessary and placed in the right home for them. You may
Find a rescue near you starting at
American Kennel Club - Breed Rescue The rescues charge a fee to help cover their expenses, but is much less than the price of a puppy plus all its medical expenses the first year.
On the biting issue. It is quite natural for puppies to bite. Any dog will play bite at least when younger. Unless trained that it is unacceptable to bite people, older dogs will bite to get their own way. I had my 12 week old Xanthe at church this morning and she bite everybody she got a chance to.
Hitting the dog is not how you teach it not to bite or anything else.
If you post your location, When RubyPitbull get back from having a life, she may be able to use her contacts to steer you to a rescue in your area.